Exposure meter

ABSTRACT

An exposure meter has both function of an incident light type exposure meter for measuring an exposure value of an object by an incident light to the object and a reflected light type exposure meter for measuring exposure value of the object by a reflected light from the object. A latitude of a film is calculated from the exposure value by the incident light. The exposure value by the incident light and an upper and a lower limit values of the latitude are displayed on a display device. At least one exposure value measured by the reflected light is further displayed on the display device comparably with the latitude.

[0001] This application is based on patent applications 2000-280381 and 2000-280382 filed in Japan, the contents of which are hereby incorporated by references.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an exposure meter which can sense an illuminance of an object by incident light to and reflected light from the object.

[0004] 2. Description of the Related Art

[0005] There are two types of conventional exposure meters such as an incident light exposure meter and a reflected light exposure meter. The incident light exposure meter directly senses the intensity of the incident light illuminating an object. The reflected light exposure meter senses the intensity of the reflected light from the object. The incident light exposure meter and the reflected light exposure meter are used properly corresponding to the kind of the object or the photographing condition for deciding exposure condition such as a shutter speed and an aperture number of a taking lens of a camera.

[0006] When a contrast of the object is much higher, it is difficult to include the highlight portion having the highest illuminance value (or the largest exposure value) and the shadow portion having the lowest illuminance value (or the smallest exposure value) of the object within latitude of a film. In such the case, it is necessary to decide a region of the exposure values of the portions on the object should be within the latitude of the film. Thus, the exposure values at several points on the object will be measured by the reflected light exposure meter.

[0007] It is impossible to distinguish with the exposure values at several points on the object by the incident light exposure meter, since a photo-sensing window of the incident light exposure meter must face the light source. On the other hand, the reflected light exposure meter has a disadvantage that it cannot measure the illuminance of the object precisely, since it is assumed that the reflectance of the object has a predetermined standard value, for example, 18% for calculating the exposure value. When the reflectance of the object is higher than the standard value such as the white colored object, the exposure value calculated by the reflected light exposure meter will be larger than the proper exposure value, so that the color of the object will be gray when a photograph of the object is taken under the calculated exposure value. Similarly, when the reflectance of the object is lower than the standard value such as the black colored object, the exposure value calculated by the reflected light exposure meter will be smaller than the proper exposure value, so that the color of the object will be gray when a photograph of the object is taken under the calculated exposure value. Thus, it is preferable to consider the exposure values measured by both of the incident light exposure meter and the reflected light exposure meter for deciding the exposure condition of the camera corresponding to the kind or condition of the object.

[0008] For considering the exposure values measured by both of the incident light exposure meter and the reflected light exposure meter, the exposure value of the object, which will be used as a standard exposure value for calculating the latitude of the film to be used, is measured by the incident light exposure meter, first. Subsequently, the exposure values at several important portions on the object are measured by the reflected light exposure meter. The exposure values measured by the reflected light exposure meter will be judged whether they are included in the latitude or not. Since the exposure values measured by the incident light exposure meter and the reflected light exposure meter are respectively displayed on different display devices of the exposure meters, it is troublesome and difficult to compare with the exposure values and to recognize the relation between them. Especially, when the exposure values measured by the reflected light exposure meter are not included in the latitude or barely included in the latitude, it is necessary to adjust the standard exposure value measured by the incident light exposure meter. In such the case, the display of the exposure values on the different display devices of the display meters will be the cause of the trouble in the adjustment of the standard exposure value.

SUMMERY OF THE INVENTION

[0009] A purpose of the present invention is to provide an exposure meter having both functions of the incident light exposure meter and the reflected light exposure meter by which the exposure values measured by the both functions can be compared easily. Another purpose of the present invention is to provide an exposure meter having both functions of the incident light exposure meter and the reflected light exposure meter by which the exposure values measured by the reflected light exposure meter function can easily be judged whether they are included in a latitude calculated with reference to an exposure value measured by the incident light exposure meter function.

[0010] A first exposure meter in accordance with an aspect of the present invention comprises a first meter function for measuring an exposure value based on an incident light illuminating an object, a second meter function for measuring an exposure value based on a reflected light from the object and a display device comparably for displaying the exposure values measured by the first meter function and the second meter function.

[0011] By such a configuration, the exposure values measured by the first meter function and the second meter function are be displayed on the same display device, so that it is possible to compare the exposure values at several portions of the object based on the reflected light with the exposure value of the object based on the incident light, easily.

[0012] A second exposure meter in accordance with an aspect of the present invention comprises a first meter function for measuring an exposure value based on an incident light illuminating an object, a second meter function for measuring an exposure value based on a reflected light from the object and a calculator for calculating a latitude based on the exposure value measured by the first meter function.

[0013] By such a configuration, the latitude of a film which will be used for taking a photograph can be calculated by the calculator based on the exposure value measured by the first meter function, so that it is possible to compare the exposure values at several portions of the object based on the reflected light with the latitude, easily.

[0014] As a result, an exposure condition, by which the highlight portion and the shadow portion of the object are included in the latitude of the film, can be decided, easily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a front view of an exposure meter in accordance with an embodiment of the present invention;

[0016]FIG. 2 is a rear view of the exposure meter in accordance with the embodiment;

[0017]FIG. 3 is a block diagram for showing a configuration of the exposure meter in accordance with the embodiment;

[0018]FIG. 4 is a flowchart for showing an operation of the exposure meter in accordance with the embodiment for deciding an exposure condition of a photograph;

[0019]FIG. 5 is a front view for showing an example of a display on a display device of the exposure meter in accordance with the embodiment;

[0020]FIG. 6 is a front view for showing another example of the display on the display device of the exposure meter in accordance with the embodiment;

[0021]FIG. 7 is a front view for showing an example of a display in a viewfinder of the exposure meter in accordance with the embodiment;

[0022]FIG. 8 is a front view for showing another example of the display in the viewfinder of the exposure meter in accordance with the embodiment;

[0023]FIG. 9 is a front view for showing still another example of the display in the viewfinder of the exposure meter in accordance with the embodiment;

[0024]FIG. 10 is a front view for showing still another example of the display in a viewfinder of the exposure meter in accordance with the embodiment;

[0025]FIG. 11 is a block diagram for showing a configuration of a modification of the exposure meter in accordance with the embodiment;

[0026]FIG. 12 is a flowchart for showing a method for adjusting compensation factors “C” and “K” which are used for calculating the exposure values;

[0027]FIG. 13 is a front view for showing still another example of the display on the display device of the exposure meter in accordance with the embodiment, when a standard exposure value is adjusted; and

[0028]FIG. 14 is a front view for showing still another example of the display on the display device of the exposure meter in accordance with the embodiment, when widths of a latitude of a film are adjusted.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0029] An embodiment of the present invention is described with reference to the figures.

[0030] A front view and a rear view of an exposure meter 1 in accordance with the embodiment are respectively shown in FIGS. 1 and 2. The exposure meter 1 is configured for measuring an exposure value or an illuminance of an object by using both of an incident light illuminating the object and a reflected light of the illumination light reflected by the object.

[0031] As can be seen from FIG. 1, an incident light type photo-sensing unit 3 including a photo-sensing sphere 3 a and so on is mounted above a main body 2 of the exposure meter 1. The photo-sensing sphere 3 a is disposed on substantially the same plane of a front face 2 aof the main body 2. A view finder 5 for observing an area at which an exposure value is to be measured is provided at an upper left portion of the front face 2 a of the main body 2. A display device 6 such as a liquid crystal display is provided substantially at the center of the front face 2 a of the main body 2, on which information such as measurement result and so on can be displayed. A main switch 7 for switching on and off of an electric power of the exposure meter 1 is provided at an upper right portion of the front face 2 a of the main body 2. A plurality of switches 42 to 46 are arranged below the display device 6 on the front face 2 a of the main body 2. For example, the switch 42 is a function switch for selecting the function of the exposure meter 1 between the incident light type exposure meter and the reflected light type exposure meter.

[0032] As can be seen from FIG. 2, a window 4 a of a reflected light type photo-sensing unit 4 is provided at an upper center of a rear face 2 b of the main body 2. A main control unit 8 including a CPU, a RAM, a ROM and so on is provided inside the main body 2. An operation switch 41 and a control dial 47 are provided on a side face 2 c of the main body 2. The operation switch 41 is operated for switching on and off of the measurement of the exposure value. When the operation switch 41 is pushed down, the exposure value or the illuminance of the object is measured.

[0033] A block diagram of the exposure meter 1 is shown in FIG. 3. An incident light system is configured by a first photo-electro converter 21 such as a photodiode for converting light energy of an incident light to a current signal, a first integration circuit 22 for converting the current signal to a voltage signal, and a first compensation circuit 23 for compensating a sensitivity of measurement by amplifying the voltage of the voltage signal outputted from the first integration circuit 22. Similarly, a reflected light system is configured by a second photo-electro converter 31 for converting light energy of a reflected light from an object to a current signal, a second integration circuit 32 for converting the current signal to a voltage signal, and a second compensation circuit 33 for compensating a sensitivity of measurement by amplifying the voltage of the voltage signal outputted from the second integration circuit 32.

[0034] The first compensation circuit 23 and the second compensation circuit 33 are respectively connected to a switching circuit 11. The switching circuit 11 alternatively switches the function of the exposure meter 1 between the incident light type exposure meter and the reflected light type exposure meter corresponding to the operation of the function switch 42. An A/D converter 12 connected to the switching circuit 11 converts the analogous voltage signals from the first compensation circuit 23 and the second compensation circuit 33 to digital signals. A calculator 13 connected to the A/D converter 12 calculates not only an exposure value of an object corresponding to each output signal of the A/D converter 12 but also a latitude based on the exposure value corresponding to the output signal from the incident light system. The exposure values and upper and lower limit values of the latitude are inputted to a display circuit 14 for displaying them on the display device 6.

[0035] When the exposure meter 1 is used as the incident light type exposure meter, the exposure meter 1 is oriented in a manner so that the photo-sensing sphere 3 a faces a light source of an illumination light such as the sun. The light energy of the incident light passes through the photo-sensing sphere 3 a and reaches to the first photo-electro converter 21 provided behind the photo-sensing sphere 3 a in the incident light type photo-sensing unit 3. The output signal from the first photo-electro converter 21 is processed as mentioned above, the exposure value of the object and the upper and lower limit values of the latitude based on the incident light of the illumination light are displayed on the display device 6.

[0036] When the exposure meter 1 is used as the reflected light type exposure meter, the exposure meter 1 is oriented in a manner so that the window 4 a of the reflected light type photo-sensing unit 4 and the view finder 5 face the object. The light energy of the reflected light from the object passes through the window 4 a and reaches to the second photo-electro converter 31 provided behind the window 4 a in the reflected light type photo-sensing unit 4. The output signal from the second photo-electro converter 31 is processed as mentioned above, the exposure value of the object based on the reflected light from the object is displayed on the display device 6.

[0037] The display circuit 14 includes a memory for memorizing a plurality of exposure values and the upper and lower limit values of the latitude. For example, when several points on the object are measured for calculating the exposure values in the function of the reflection light type exposure meter, the exposure values corresponding to the measured points are memorized in the memory and can be displayed on the display device 6 at the same time.

[0038] Operation of the exposure meter 1 for deciding an exposure condition of a photograph will be described with reference a flowchart shown in FIG. 4.

[0039] At first, an exposure value of an object is measured by the function of the incident light type exposure meter (Step S11). The function of the incident light type exposure meter of the exposure meter 1 is selected by operating the function switch 42. The exposure value based on the incident light is used as a standard exposure value for calculating the upper and lower limit values of the latitude. The calculated upper and lower limit values of the latitude are displayed on the display device 6 (Step S12).

[0040] Subsequently, the function of the exposure meter 1 is switched to the reflected light type exposure meter by operating the function switch 42 (Step S13). At least one (preferably, a plurality of) important point on the object is measured by reflected light from the object for calculating the exposure value (Step S14).

[0041] The exposure value (EV) and the upper and lower limit values of the latitude based on the incident light and the exposure values (EVs) based on the reflected light are comparably displayed on the display device 6 or in the view finder 5 (Step S15). Display of these values are not necessarily displayed at the same time, if they are comparable.

[0042] When the exposure values are calculated, the main control unit 8 judges whether the exposure values (EVs) based on the reflected lights from the important portions of the object are included in the upper and lower limit values of the latitude based on the incident light or not (Step S16).

[0043] When at least one exposure value of the important portion of the object is not included in the latitude (NO in Step S16), the main control unit 8 outputs an alarm (Step S17). When the alarm is outputted, the user can adjust the standard exposure value and the upper and lower limit values of the latitude corresponding to his taste (Step S18).

[0044] It is preferable to measure the exposure values of the important portions of the object by the reflected lights (Step S19). The exposure values newly measured and the adjusted latitude are displayed on the display device 6 or in the viewfinder 5 (Step S15), and judged whether the exposure values newly measured are included in the adjusted latitude or not (Step S16). When the exposure values of the important portions on the object are included in the latitude or the adjusted latitude (YES in Step S16), the standard exposure value or the adjusted standard exposure value can be used for deciding the exposure condition.

[0045]FIG. 5 shows an example of the display on the display device 6. In this example, the standard exposure value A1, the upper limit value H1 and the lower limit value Si of the latitude are indicated above an analogous scale 61 laterally disposed and the exposure values R1, R2 . . . of the important portions on the object is indicated below the analogous scale 61. These indication are disposed at upper portion on the display device 6. A shutter speed (exposing time) 62, an aperture number 63, a sensitivity of a film 64 by ISO standard, a light indication 65 for distinguishing a kind of the illumination light such as ambient light “AMBI” or flash light “FLASH” and a function indication 66 for distinguishing the function of the exposure meter 1 between the incident light exposure meter “In” and the reflected light exposure meter “Ref” are further displayed on the display device 6.

[0046] Hereupon, the calculation of the upper and lower limit values of the latitude is described. For example, when a film to be used has a latitude of 5 steps of the exposure value (5EV) by APEX indication, the upper region of the latitude with respect to the standard exposure value is optionally selected to be 2.3 steps of the exposure value (+2.3 EV) and the lower region of the latitude is selected to be 2.7 steps of the exposure value (−2.7 EV). When the standard exposure value is EV10, the upper limit value H1 of the latitude is calculated as EV12.3 (EV10 +2.3 EV=EV12.3) and the lower limit value S1 is calculated as EV7.3 (EV10−2.7 EV=EV7.3).

[0047] In the example shown in FIG. 5, the exposure value R2 based on the reflected light is larger than the upper limit value H1 of the latitude, so that the main control unit 8 displays an alarming mark 67 for showing the overexposure. Alternatively, when any exposure value based on the reflected light is smaller than the lower limit value S1 of the latitude, another alarming mark 68 showing the underexposure will be displayed. By such the alarming, the user can know that the current standard exposure value is improper for taking a properly exposed photograph. Method for alarming the improper is not restricted by the alarming marks 67 and 68. It is possible to output an alarming sound, an alarming lighting, or the like.

[0048] As mentioned above, the standard exposure value A1 based on the incident light and the upper limit value H1 and the lower limit value S1 of the latitude are comparably displayed on the display device 6 with the exposure values R1, R2 . . . at the important portions of the object, so that it is easily possible to decide the standard exposure value used for taking a photograph by which the exposure values at the important portions of the object can me included in the latitude of the film. Furthermore, a relation between the latitude and the exposure values at the important portions of the object is analogously displayed, so that it is easily possible to adjust the standard exposure value in a manner so that the exposure values at the important portions of the object will be included in the latitude of the film.

[0049]FIG. 6 shows another example of the display on the display device 6. In this example, the standard exposure value A2, the upper limit value H2 and the lower limit value S2 of the latitude are indicated at right side of an analogous scale 61B longitudinally disposed and the exposure value R3 . . . of the important portions on the object is indicated at further right side of the analogous scale 61B. Since the exposure value R3 based on the reflected light is smaller than the lower limit value S2 of the latitude, the main control unit 8 alarms the underexposure by flickering the indication of the exposure value R3.

[0050]FIG. 7 shows an example of the display in the viewfinder 5 which is used for measuring the exposure values by the function of the reflected light type exposure meter. A spot circle 52 for showing a measuring area is disposed at the center of a rectangular frame 50. A lateral analogous scale 51 is disposed below the frame 50. With respect to the scale 51, the standard exposure value A3 based on the incident light and the exposure value R4 based on the reflected light are respectively indicated by marks of “Δ”. Furthermore, the aperture number (Fno.) 53, which is calculated from the exposure value based on the reflected light, is numerically displayed below the analogous scale 51.

[0051]FIG. 8 shows another example of the display in the viewfinder 5. A longitudinal analogous scale 51 is disposed at right side of the frame 50. With respect to the scale 51, the standard exposure value A3 based on the incident light and the exposure value R4 based on the reflected light are respectively indicated by marks of “Δ” The aperture number (Fno.) 53 is numerically displayed below the analogous scale 51.

[0052] In the examples shown in FIGS. 7 and 8, it is preferable further to indicate the upper and lower limit values of the latitude with respect to the analogous scale 51. Alternatively, it is preferable to correspond the length of the analogous scale 51 with the latitude.

[0053]FIG. 9 shows still another example of the display in the viewfinder 5. In comparison with the example shown in FIG. 7, the exposure value (EV) 53 a is numerically displayed below the analogous scale 51 instead of the aperture number (Fno.) 53. In the example shown in FIG. 9, the exposure value based on the reflected light is smaller than the lower limit value of the latitude, so that an alarming mark 54 is indicated for showing the underexposure.

[0054]FIG. 10 shows still another example of the display in the viewfinder 5. In this example, the exposure value 53 c based on the reflected light is numerically displayed below the center of the frame 50. The upper limit value 57 and the lower limit value 56 of the latitude are numerically displayed at both side of the exposure value 53 c. No analogous scale is displayed. In this example, the alarming mark 54 shows the under exposure, since the exposure value 53 c displayed at the center is smaller than the lower limit value 56. Since the exposure value and the upper and lower limit values of the latitude are numerically displayed, the user can easily recognize the relation between the exposure value at the important portion of the object and the latitude of the film.

[0055] As mentioned above, since the standard exposure value based on the incident light and/or the upper and lower limit values of the latitude is/are displayed in the view finder in the examples shown in FIGS. 7 to 10, the user can recognize whether the exposure value at the important portion of the object is included in the latitude or not instantaneously at the measurement of the exposure value observing the object through the viewfinder 5.

[0056] Subsequently, the calculation of the exposure values is described. The exposure value (EV) based on the incident light in the incident light type exposure meter satisfies the following equation (1).

2^(EV) =A ² /T=ES/C  (1)

[0057] Hereupon, the symbol “A” designates the aperture number (Fno.). The symbol “T” designates the shutter speed or the exposing time. The symbol “E” designates an illuminance at the photo-sensing sphere 3 a of the incident light type photo-sensing unit 3. The symbol “S” designates a sensitivity (or an exposure index) of a film. The symbol “C” designates a compensation factor for compensating the sensitivity of the exposure meter in the incident light type exposure meter.

[0058] The exposure value (EV) based on the reflected light in the reflected light type exposure meter satisfies the following equation (2).

2^(EV) =A ² /T=LS/K  (2)

[0059] Hereupon, the symbol “A” designates the aperture number (Fno.). The symbol “T” designates the shutter speed or the exposing time. The symbol “L” designates a luminance of a light source which is used in the calibration of the exposure meter. The symbol “S” designates a sensitivity (or an exposure index) of a film. The symbol “K” designates a compensation factor for compensating the sensitivity of the exposure meter in the reflected light type exposure meter.

[0060] In the exposure meter 1 having both function of the incident light type exposure meter and the reflected light type exposure meter, it is necessary to adjust the compensation factors “C” and “K” with a preferable balance.

[0061] A modification of the block diagram of the exposure meter 1 is shown in FIG. 11, in which the compensation factors “C” and “K” can be adjusted, independently.

[0062] An incident light system is configured by a first photo-electro converter 21 for converting light energy of an incident light to a current signal, and a first integration circuit 22 for converting the current signal to a voltage signal. Similarly, a reflected light system is configured by a second photo-electro converter 31 for converting light energy of a reflected light from an object to a current signal, and a second integration circuit 32 for converting the current signal to a voltage signal.

[0063] The first integration circuit 22 and the second integration circuit 32 are respectively connected to a switching circuit 11. The switching circuit 11 alternatively switches the function of the exposure meter 1 between the incident light type exposure meter and the reflected light type exposure meter corresponding to the operation of the function switch 42. An A/D converter 12 connected to the switching circuit 11 converts the analogous voltage signals from the first integration circuit 22 and the second integration circuit 32 to digital signals. A calculator 13 connected to the A/D converter 12 calculates not only an exposure value of an object corresponding to each output signal of the A/D converter 12 but also a latitude based on the exposure value corresponding to the output signal from the incident light system.

[0064] A first compensation factor selector 24 and a second compensation factor selector 34 are respectively connected to the calculator 13. The first compensation factor selector 24 selects the value of the compensation factor “C” used in the equation (1) when the switching circuit 11 selects the incident light system. The second compensation factor selector 34 selects the value of the compensation factor “K” used in the equation (2) when the switching circuit 11 selects the reflected light system. The exposure values and upper and lower limit values of the latitude calculated by the calculator 13 are inputted to a display circuit 14 for displaying them on the display device 6.

[0065] By such a configuration, the compensation factors “C” and “K” can independently be adjusted, so that the sensitivities of the measurements by the incident light and the reflected light can independently be compensated by the adjusted compensation factors ‘C” and “K”.

[0066] Generally, the exposure value measured by the incident light type exposure meter shows a condition that an image of a standard object having a reflectance of 18% exposed on a film will be reproduced for having a middle density. The exposure value measured by the reflected light type exposure meter shows a condition that an image of a portion of an object at which the exposure value is measured will be reproduced for having the middle density. Hereupon, the middle density is defined that a density having the center value on the logarithmic abscissa in an effective exposure region of a characteristic curve of a film.

[0067] Method for adjusting the compensation factors “C” and “K” is described with reference to a flowchart shown in FIG. 12. The compensation factor “C” for the incident light type exposure meter is adjusted first.

[0068] At first, the exposure value of the object is measured by the function of the incident light type exposure meter (Step S21). Subsequently, a photograph of the object is actually taken under an exposure condition decided by the exposure value, and the photograph is evaluated (Step S22). If the evaluation of the photograph cannot be satisfied, the value of the compensation factor “C” is adjusted by the first compensation factor selector 24 corresponding to the user's taste (Step S23). Hereupon, the steps S21 to S23 can be repeated until the satisfying evaluation of the photograph can be obtained.

[0069] When the compensation factor “C” is fixed, a standard object, which will be used for coinciding an exposure value measured by the reflected light with the exposure value measured by the incident light, is selected (Step S24). Generally an object having a reflectance of 18% is selected. The exposure values of the standard object are measured by both of the incident light and the reflected light (Steps S25 and S26). Subsequently, the exposure values measured by the incident light and the reflected light are compared with each other (Step S27). When the exposure values measured by the incident light and the reflected light are not coincided with each other, the compensation factor “K” is adjusted in a manner to coincide the exposure values with each other (Step S28).

[0070] The exposure values measured by the exposure meter are generally proper, since the above-mentioned compensation factors “C” and “K” are experimentally obtained. It, however, is not necessarily proper, since the proper exposure will vary corresponding to the photographing condition, the user's taste, and so on. When the user's taste tends to be biased highkey or lowkey, it is preferable to adjust the compensation factors “C” and “K” for showing proper exposure values fitting to the user's taste, for example, by selecting the reflectance of the standard object to be a value except 18%.

[0071] In the above-mentioned exposure meter 1 shown in FIG. 1, when a standard value setting switch 43 is switched on, the exposure value measured by function of the incident light type exposure meter is set as the standard exposure value A1. Simultaneously the upper limit value H1 and the lower limit value S1 of the latitude are calculated by basing on the standard exposure value A1. The standard exposure value A1, the upper and lower limit values H1 and S1 of the latitude are displayed on the display device 6 and/or indicated in the viewfinder 5.

[0072] For adjusting the latitude, the control dial 47 is rotated while a standard value adjusting switch 44 is pushed on. As shown in FIG. 13, the standard exposure value A1, the upper and lower limit values H1 and S1 of the latitude are respectively shifted by the same quantity in the same direction corresponding to the rotation angle of the control dial 47. By such the operation, the exposure value R1 at the important portion of the object can be included in the latitude.

[0073] For adjusting the compensation factor “C” in the function of the incident light type exposure meter, an adjusting mode switch 46 is cyclically pushed on so as to select the mode for adjusting the compensation factor “C” . Subsequently, the A control dial 47 is rotated so that the compensation factor “C” will be adjusted corresponding to the rotation angle of the control dial 47.

[0074] For adjusting the compensation factor “K” in the function of the reflected light type exposure meter, the adjusting mode switch 46 is cyclically pushed on so as to select the mode for adjusting the compensation factor “K”, and the control dial 47 is rotated.

[0075] For adjusting the exposure value by the incident light and the region of the latitude, the adjusting mode switch 46 is cyclically pushed on so as to select the mode for adjusting the exposure value by the incident light, and the control dial 47 is rotated.

[0076] For adjusting the widths of the latitude, the adjusting mode switch 46 is cyclically pushed on so as to select the mode for varying the widths of the latitude, and the control dial 47 is rotated. For example, when the widths of the latitude are selected +2.3 EV and −2.7 EV with respect to the standard exposure value A1, and the standard exposure value is EV10, the upper limit value H1 of the latitude is EV12.3 and the lower limit value S1 of the latitude is EV7.3. When the control dial 47 is rotated so as to shift the widths of the latitude are to be +2.6 EV and −3.0 EV with respect to the standard exposure value A1, the upper limit value H1 of the latitude is shifted to the value H2 showing EV12.6 and the lower limit value S1 of the latitude is shifted to the value S2 showing EV7.0, as shown in FIG. 14. Thus, since the widths of the latitude are expanded, the exposure value R1 measured by the reflected light can be included in the latitude.

[0077] As mentioned above, the exposure meter 1 in accordance with the embodiment of the present invention can adjust the standard exposure value measured by basing on the incident light, the widths of the latitude, the compensation factors “C” and “K” used for calculating the exposure values, and so on. Thus, it is possible to decide the proper exposure value or exposure condition in view of the user's taste and the experiences.

[0078] Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. 

What is claimed is
 1. An exposure meter comprising: a first meter function for measuring an exposure value based on an incident light illuminating an object; a second meter function for measuring an exposure value based on a reflected light from the object; and a display device comparably for displaying the exposure values sensed by the first meter function and the second meter function.
 2. The exposure meter in accordance with claim 1, wherein the display device displays a plurality of measurement results by the second meter function.
 3. The exposure meter in accordance with claim 1, wherein the display device analogously displays at least a measurement result by the first meter function or a measurement result by the second meter function with respect to an analogous scale.
 4. The exposure meter in accordance with claim 3, wherein the display device displays the measurement result by the first meter function in the opposite direction to the measurement result by the second meter function with respect to the analogous scale.
 5. The exposure meter in accordance with claim 3, wherein the display device displays the measurement result by the first meter function in the same direction with the measurement result by the second meter function with respect to the analogous scale.
 6. The exposure meter in accordance with claim 3, wherein the display device numerically displays the measurement result by the second meter function.
 7. The exposure meter in accordance with claim 1, wherein the display device numerically displays the measurement result by the first meter function and the measurement result by the second meter function.
 8. The exposure meter in accordance with claim 1, wherein the display device further displays a region of a latitude which is based on the measurement result by the first meter function.
 9. A second exposure meter comprising: a first meter function for measuring an exposure value based on an incident light illuminating an object; a second meter function for measuring an exposure value based on a reflected light from the object; and a calculator for calculating a latitude based on the exposure value measured by the first meter function.
 10. The exposure meter in accordance with claim 9 further comprising a display device for displaying a region of the latitude calculated by the calculator.
 11. The exposure meter in accordance with claim 10, wherein the display device further displaying a measurement result by the second meter function in a manner to be judged whether the measurement result is included in the latitude or not.
 12. The exposure meter in accordance with claim 11 further comprising an indicator for alarming that the measurement result by the second meter function is out of the latitude.
 13. The exposure meter in accordance with claim 10 further comprising a viewfinder, and wherein the display device is provided in the viewfinder.
 14. The exposure meter in accordance with claim 13 further comprising an indicator for alarming that the measurement result by the second meter function is out of the latitude, and wherein the indicator is provided in the viewfinder.
 15. The exposure meter in accordance with claim 9 further comprising a setter for setting widths of the latitude with respect to a standard value.
 16. The exposure meter in accordance with claim 9 further comprising a first adjuster for adjusting a compensation factor used for calculating a measurement result in the first meter function, and wherein the calculator calculates a region of the latitude by using the adjusted compensation factor.
 17. The exposure meter in accordance with claim 16 further comprising a second adjuster for adjusting a compensation factor used for calculating a measurement result in the second meter function.
 18. The exposure meter in accordance with claim 9 further comprising a third adjuster for adjusting a region of the latitude calculated by the calculator. 